1. FP420 Vacuum Ray Veness

2. Contents o What is FP420? o How would it be installed in the LHC? o What would it look like? o What are the issues/interest for our group? Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

3. What is FP420? o What does it stand for? o FP420 = Forward Physics at 420 m (in the LHC) o What is it? o Currently an international R&D Project o Plan to add new detectors at 220 m and 420 m either side of IP 1 and/or 5 o Technical proposals being prepared in ATLAS and CMS experiments o Would become part of one or both of these experiments if approved o How does it work? o Higgs discovery mechanism using the LHC dipole magnets as a spectrometer o Higgs produced at the IP from two colliding protons o These protons remain intact and continue along the beam axis having lost a fraction of their energy o When these protons go through the machine dipoles (separation and dispersion suppressor) they are separated from the circulating beam by the magnetic field o Insert (silicon) detectors very close to beam ~5 mm (20σ) o Detect these particles and precisely measure their arrival time o Use this data, along with detectors in the central detector to re-construct the event Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

4. Layout o Main issues o 420 m from the IP is inside the continuous cryostat between Q10 and Q11 o 220 m is occupied by TOTEM roman pots in IR5 Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

5. Add a New Warm Sector o Design o Use modified Arc Termination Modules (ATM) o Standard VAB-type vacuum instrumentation assemblies o Leaves ~7.6 m warm space for detectors Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness 3D view of proposed new warm sector, replacing connecting cryostat

6. ATM details Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness Schematic positions of magnet lines 3D part-section of modified ATM (T.Renaglia) ATM and VAB from warm sector

7. Layout in the Warm Sector o Main issues o Detectors need to move in and out of the beam o Detector geometry not compatible with ‘standard’ roman pots o 2 detector stations need to be as far as possible from each other Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

8. ‘Hamburg Beampipe’ Proposal o Concept o Move the entire vacuum chamber, complete with detectors and BPMs in and out of the beam o A long, thin-walled ‘pocket’ contains the detectors o Detectors remain in air o System can be baked-out before detector insertion (as with LHC roman pots) o Design o Ongoing, by FP420, ATLAS and CMS, but… o I am pushing them to use standard LSS components wherever possible o Bellows modules for lateral movements o LSS-type BPMs Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness Figures courtesy of: J.Pater JoP 110 (2008) 092022 Thin-walled ‘pocket’ for silicon detectors ‘Hamburg Beampipe’ Schematic

9. Summary o Current status o CERN have produced a mechanical design for the new ATM o Technical Proposals are being prepared with a view to an installation in 2010/11 shutdown at the earliest o Next steps o FP420 would like to discuss with VSM early next year with a view to a collaboration, with possible subjects including: o Design and test of (near) standard LSS components for the moving beampipe o Impact on the LHC beam vacuum of this additional warm sector o Consultancy (or more) on the thin window for the detector pocket o Are there any ‘show-stoppers’ for the vacuum system? o Dynamic vacuum issues related to a warm sector in the dispersion suppressor? o Synchrotron radiation? o Mechanical risks? o Additional risk of venting the continuous cryostat? o Detector will not retract from beam (risk also for roman pots) Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

10. Additional Material Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness

11. Vac Sci.&Proj. 15 XII 08FP420 Vacuum- R.Veness Bellows unit: Standard Options o Standard LHC LSS: L total = 1215 mm o Existing standard LSS component designs, used with offsets as specified for the LSS o ‘Optimised LSS’: L total ~500 mm o Existing standard LSScomponent designs, using offsets considered acceptable for 500 cycles by the bellows manufacturer o Additional testing would be required to verify acceptability for 4000 cycle (FP420?) lifetime. L total LSS warm module LSS drift vacuum chamber